The invention relates to safety devices for primary explosive detonators, particularly to a circuit to protect a primary explosive detonator from electro-static discharge (ESD), and more particularly to a circuit containing an energy storage capacitor and preset self-trigger to protect the primary explosive detonator from ESD.
Detonators, such as the Silicon Bridgewire (SCB) detonator technology is known in the art. SCB detonators are sensitive to electro-static discharge (ESD) and are not fast functioning devices. Traditional ESD protection for SCBs incorporate zener diodes into the structure which have the disadvantage of degrading the performance. In an attempt to enhance the performance of the device, a small circuit, made in accordance with the present invention, was incorporated with the detonator for the purpose of delivering energy very rapidly. This circuit also has the advantage of providing ESD protection to the detonator. Primary explosive detonators are used in a number of applications, such as in the automotive airbag industry, and the circuit of this invention can contribute to public safety by enhancing the safety of the device against pre-fire, and the performance of the device against misfire. Basically, the circuit of the present invention includes an energy storage capacitor operatively connected to a primary explosive detonator, a voltage sensing trigger, and a switch device.